Multi-Port Amplifier Leakage Calibration With Closed-Loop Gain Correction
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Solution Overview
Problem
Current calibration methods for multi-port amplifiers (MPAs) operating at Ku/Ka frequency bands face challenges in accurately monitoring and minimizing port-to-port leakages, with limitations due to measurement tolerances, passive component imperfections, and intermodulation noises, particularly in maintaining leakage performance over the required service life.
Innovation Solution
A calibration system and method that monitors and optimizes leakage performance onboard a satellite using a calibration signal generator, detector, and error correction algorithms, allowing for flexible calibration frequency and amplitude settings, and optional onboard or ground-based processing to adjust complex gain errors, thereby minimizing leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional calibration methods are used to measure gain and phase of individual amplifiers, then calibration can be performed, but calibration accuracy is limited by measurement tolerances and passive component imperfections
Solution Approach 1:
The patent implements a feedback mechanism where the actual leakage levels are measured and used to adjust the complex gain of individual amplifiers. The system continuously monitors the leakage performance and feeds this information back to the calibration controller, which then modifies the amplifier gains to minimize leakage. This closed-loop feedback approach overcomes the limitations of open-loop calibration methods by actively compensating for measurement tolerances and component imperfections.
Solution Approach 2:
The calibration system uses the MPA's own output signals to perform self-calibration. By measuring the leakage levels of its own output and using this information to adjust its own amplifier gains, the system performs self-service calibration without requiring external calibration equipment or additional hardware beyond what is already present in the MPA structure.
2Ease of operation
If calibration signals are injected using couplers within the IHM or detected using couplers within the OHM, then calibration can be performed, but the IHM/OHM performance is affected and calibration accuracy is limited by hybrid imperfection
Solution Approach 1:
The patent extracts the calibration measurement function from the signal path by using directional couplers to tap off a portion of the output signal for leakage measurement. Instead of injecting calibration signals through the IHM couplers or detecting through OHM couplers (which would affect hybrid performance), the system uses separate coupling paths to measure leakage without degrading the main signal transmission through the hybrids.
3Adaptability or versatility
If a priori knowledge of unit transfer matrices is used for matrix manipulations, then calibration can be performed, but calibration accuracy is limited by measurement tolerances and passive component imperfections
Solution Approach 1:
The patent changes the calibration approach from using fixed a priori transfer matrix knowledge to dynamically measuring actual leakage levels and adjusting complex gain parameters accordingly. Instead of relying on predetermined matrix relationships that are subject to tolerance accumulation, the system measures the actual operating conditions and adjusts parameters in real-time to achieve optimal leakage performance.
4Reliability
If MPA calibration is performed onboard the satellite, then leakage performance can be monitored and optimized, but system complexity increases
Solution Approach 1:
The patent implements multi-functionality by using the same output amplifiers and signal paths for both normal signal transmission and calibration measurements. The calibration system reuses existing MPA components (amplifiers, hybrids, couplers) for dual purposes: signal processing during operation and leakage measurement during calibration. This eliminates the need for separate dedicated calibration hardware, reducing overall system complexity while enabling onboard calibration capability.
Data Source
AI summary
A calibration system of architecture, apparatus, algorithms and method for optimizing leakage performance of a multi-port amplifier (MPA) for satellite communications. The calibration system comprises simple onboard apparatus and generally on-ground algorithms implementation connected via telecommand and telemetry links. The isolation performance of the MPA is monitored by using a commandable frequency generator and a flexible narrowband receiver. The high performance is achieved by direct and efficient optimization of the aggregate leakage of the MPA. The calibration system may be applied but not limited to Ku and Ka-band high throughput satellite systems.